he effect of extrusion blow molding machine and choice

A total of extrusion blow molding machine/include extruder (two or more), head, clamping device, mould, etc. It is similar to extrusion blow molding (single) molding equipment, the main difference is that a total of extrusion system and the extrusion.

Extrusion system

Extrusion system consists of two above extruder and the transporting pipe. In a total of extrusion, extrusion machine must at the same time to the nose a few strands of the same or different materials of molten material flow, and these melt extrusion conditions and often have different melt flow rate, sometimes even have bigger difference. Extrusion system, therefore, the most important thing is to ensure that each layer of the melt flow stability and uniformity.

(1) extruder

(1) the effect of extruder with good plasticizing uniform and stable melt flow, to ensure the uniform distribution of each layer thickness.

(2) the selection of extruder extruder selection is not much difference with single extrusion blow molding machine, only need to pay attention to the following questions.

A. when resin at the grass-roots level to choose PP, PE, can use ordinary gradient type screw, PA mutant screw. EVOH is L/D to the requirement of screw acuity 25:1, compression ratio (3.0 4.0) : 1, try to minimize the stranded, suggested that EVOH do not use the screw with mixing section.

B. the size of the extruder with composite containers with recycle and wall thickness than the match. Main floor with the extruder should be big enough, the isolation layer, bonding layer with extruder smaller accordingly.

C. use metering feeder, control the amount of material into the extruder. Through metering charging, control extruder extrusion capacity, make each stage of extruder extrusion quantity can and setting the proportion of consistent; Can also monitor the extrusion machine materials consumption ratio, to achieve accurate thickness ratio in the layers of material.

D. selection in the feeding section has extruder cylinder slot liner, cylinder slot make the feed zone produces high pressure, to stabilize the extruder operation; But this kind of high pressure will produce high shear, make the material heated up fast. Therefore, we need to in the feeding section of the cylinder to provide powerful cooling measures, and insulation and other areas.

E. the output of the melt pump with high precision, improve the stability of the melt output. The extrusion machine melt through the feeding tube into the nose, the channel length is different, the melt pressure loss is different also. After using the melt pump, into the nose of the melt the required pressure is provided by the melt pump. Make the melt is not affected by any changes to the extrusion process, the stability of the output material has nothing to do with the input. L brand